1. FIELD OF THE INVENTION
The present invention relates to an ink injection method for injecting an ink into an ink containing chamber of an ink tank, an ink injection device, and an ink-jet recording apparatus provided with the device.
2. RELATED BACKGROUND ART
In a recording head provided in an ink-jet recording apparatus of this kind, since ink is consumed during image formation, it is necessary to supply the recording head with ink normally.
As an ink supply system to the recording head, there is known a method in which an ink tank is provided at a position different from that of a carriage, and the ink tank is connected to the recording head through a tube. In this case, to the recording head, a head difference between the ink tank and the recording head is utilized to supply the ink.
Further, there is a type detachably provided with an ink tank for generating a negative pressure relative to the recording head inside the tank. As a method in one form, there is a method which adopts a head cartridge capable of integrally including the recording head and the ink tank. As an easiest method for generating a negative pressure in the ink tank, a method utilizing a capillary force of a porous body (ink holding body) can be used. There is a proposal about a construction in Japanese Patent Application Laid-open No. 125232/1995 applied by the applicant in which with the aim of solving the problem of porous body of relatively low ink containing efficiency per a unit of volume and to achieve stable ink supply, a porous body is inserted in part of an ink tank.
FIG. 5 shows a schematic sectional diagram of an ink tank utilizing the above-described construction. Inside of an ink tank 101 is partitioned into two spaces by a partition wall 103 having a communicating hole 102. One space is an enclose space except for the communicating hole 102 of the partition wall 103. This space forms an ink containing chamber 104 for keeping the ink, as is, without mixing with other materials. The other space forms an ink holding body containing chamber (atmosphere communicating liquid containing chamber) 106 for containing an ink holding body 105. On the wall surface forming the ink holding body containing chamber 106, there are formed an atmosphere communicating port 107 for introducing the air in association with an ink consumption, and a supply port 108 for supplying ink to the recording head part. In such a tank structure, when ink in the ink holding body 105 is consumed by the recording head, the air is introduced from the atmosphere communicating port 107 to the ink holding body containing chamber 106, and the air is introduced through the communicating hole 102 of the partition wall 103 into the ink containing chamber 104. In replacement with this, ink from the ink containing chamber 104 is charged to the ink holding body 105 of the ink holding body containing chamber 106 through the communicating hole 102 of the partition wall 103. Therefore, even when ink is consumed by the recording head, ink is charged to the ink holding body 105 according to the consumption amount.
Since the ink holding body 105 holds a constant amount of ink, and maintains a constant negative pressure to the recording head (this state being called "gas-liquid replacement state"), an ink supply to the recording head is stabilized. In particular, as in the description of Japanese Patent Application Laid-open No. 40043/1994, by forming a passage for introducing the atmosphere in the vicinity of the communicating part between the ink holding body containing chamber and the ink containing chamber, ever-better supply of ink to the recording head can be achieved.
In the above-described types, in either type of the head pressure utilization or negative pressure utilization, the ink tank is generally replaced with new one when the ink is exhausted.
On the other hand, in view of liquid replenishment when equipped on an apparatus of a relatively large recording amount, in such an apparatus, a large capacity tank for holding ink (hereinafter referred to as "a large tank") is provided, and a head cartridge integrally having an ink tank and a recording head is mounted on the carriage. The carriage is moved to a predetermined position, the ink tank (hereinafter referred to as "a tank part") of the head cartridge is connected to the large tank, thereby replenishing ink to the tank part. This is known as an ink supply system of a type called as a so-called pit-in.-system.
In Japanese Patent Application Laid-open No. 234881/1997 applied by the applicant, while using such a pit-in system, there is a proposal about an ink supply system and a recording apparatus with improved throughput without causing unnecessary consumption of ink with a simple construction by utilizing the ink tank shown in FIG. 5 as the "tank part".
Further, in Japanese Patent Application Laid-open No. 29318/1998 applied by the applicant, there is a proposal about an ink supply system and a recording apparatus capable of making liquid replenishment in shorter time and smoothly. Any of these inventions eliminate the need for a pump for replenishing liquid, is thus simple in construction, and is capable of constructing a compact apparatus, thus providing a superior liquid supply system.
However, for example, in the case of recording to a relatively large-sized recording medium (e.g. A0 size poster or the like), that is, requirement for down-sizing of the recording apparatus is not so high, there may be causes where generation of stable negative pressure by the tank part to the head during recording and improved ink replenishment speed may be required, rather than simplification of the apparatus construction.